Tuned inertia mass viscous damper



April 1953 B. E. O'CONNOR 2,636,399

' TUNED INERTIA MASS vIscoUs DAMPER Filed June 17, 1950 2 SHEETS-SHEET 2 77g. 5 Eq. 4

77g- 5 Kg. 6

fi zyeq7fmf Bernard 5'. O'Connor 21 Hffgz Patented Apr. 28, 1953 #UN-i "STATES m rem" o l ier:

TUNED INERTIKMASSNISCOUS :DAMPER Bernard OiOoimor, Bliffaiofi N. 122,, assignorlto .fi'oudaiiierfiershey CorporationjDtfoit, Mich, a corporation oflviiciiigan A miicationiiiune l'i, 1950,:SetialzNo;1168338 :9 Claims. (1 1 :The presentwinventionireiatesnto improvements tinvibration .dampers: andis mormespeeially d1- zreeted to overcoming sthe problem not torsional :osciliations or-ivibrationsi in rotary massessueh as is -.to ,-.*provide ,aniimproved .viscous fluid damperioperating ion the princiolezof :an inertia i-mass coupled in :vibration dampingieiation by viscous fluids-with a housing Vaciapteo. to Joe fixedto a Wi'bPeJtQry mass to Joe damped, and wherein the inertia mass has :a tuned spring eonnection with the housing.

Another: object 10f athe; invention is to provide improvements in-tu11ed inertia mass wiscous ivibration, dampers.

iAifurthersobiect of the invention is to provide .wibration ".clamping means wvhich, are highly ,iadaptable to meet --various operational requireiments.

' Other-objects,,features andiaclvantagesioi the present invention will "be, readily apparent from the following detailed description taken 4 in eongunction -With'.-th8. accompanying drawings, in

which:

Figure .-1 ;a;face elevational view, .partiaily broken away for: illustrative v purposes, showing a .tunediinertia mass vibration damper embodying features 0f the. invention.

Figure 2 is a c'iiametrical sectional :view-taken substantially on -.-the..1ine II;II.of Figure 1.

iEigures 3,-:4, -'and@6 are fragmentary radial sectional views through respective .mocii'ii ations -.of=-tuned inertia amass vibration dampers-.01 the stype zexemplifieot in the formiof figures 1 s and Althonghiseveral forms of vibration dampers waecorciing to the gresent-invention have-been shown, and wiilhereinaftervbe described indetail,u all forms 1 have certain characteristics I in nommon. fihatiisoitheyere ali oithe viscous diuiii damper type; and they .aiiembociy-a tune-d .inertia.mass wherein .the, tuned relationship @is attained by. .the. use of i a rubber t or rubber-like springrbyqvzh-ich the-inertia mass iscoupled. to an enclosing housing.

.=m.these-.olampers, the principal vibration demning or wihrational energy absorption is --effecte-i :by- :the use oi;a viscous -fluid such-as: a silicone to effect a yieidable, reiativezrnovenient resistant :coupling -between -;a inertia .mass and-ahousing-arranged to -besecuredi rigidly to o :tne .riampepl, 1 such. as :a :driven rotary I aor .torsionaiiy movable. iohject such 5a erank .shait subject ito torsional -.0sci1iations or: vibraitions. :McrespecificaHy,gen-inertia mass cor flywheeiisvso disposed in ispaced relatively parallel means. one rubber ror.rubber-likes-tunine spring housing that when '1 an-ass ,tobedamped,

A :2 t. e, ousihg moves with the -,thin films=of the viscous ifiuid intervening betweenflthe opposingiparallel Work- .inasurf-aces of ;the,'fiywhee1,or inertia mass and the adjaeent surfaces within. the housing ,provide -a .iiuid coupling betweenthe workingtsurfaces due to the, inherent-1,shearresistance of "the viscous .iiuid. That is,Lthe,viscousifluidiis present bet 'een -the .iopposing marailel ii/ orking ISurfaces .'oi the ,inertia mass andgtheghousing -in films whichfare thicker ,thamatmerelubricating film but which .aieoiliessjthicknessithanalayer which will, prosvideifor merely a fiuifd drag relationship. Stated .zanotherivay the shear films. of viscous'fiiiid are Lthe "result "of an "essentially jiiriearjv'e'i'oeit r gradient Cspacingj betweenithe opposing giarallei Wei-King surfaces of 'the members with relation to the visc0sity...of theiqampin sfiuid rather than oainon-elmear veiocity 'g'raelieiitfrelations p, .-As Ltheimain mass'toibe damp'er litenolsjto vibrate in operation ,or i.as. thes resiil'tjdf lsohie vibration in- .oucingiorce inits. environment, "the viscous fluid shear, ,lriims, ,resist -V;1miependeht [movement or 'inertia.;iso1ation 50f ithe ifne'i'tia, mass relative to theihousingito which "the 'vibr ons Y of the mass .iarertransmittedanil the vibrational energy is thus .ingsspring which imposes a :counter-actingiorce by act on or tnetmerma mass through vthe {spring 4.11.7011, the naturals-frequency vibrations of :the niamimass, thereby w( iissiloatn ig such vibrations.

, S S mper-must oeespecially-designed tor; each; -particuiar application 7 having know-n natural rrequency vibration-to be overcome, pro- VJSQLGRJKI'LZSB he mace -i'or reaciy. -a;c'iaptabihty and :versatiiityiin yconstriuction-to meet a Wiae range Q @per ims-r qmiemems. a

oinonercrm or the tuned inertia-mass-damper acooroingito the,presentunventionfiano as shown in mgures-rl -anufi, ra'casi-ng or housing-it :has tneizem-aiehamber Iii housing-a "inertia mass 42 which is operatively attaohedsto. the housing Joy iii. For brevity in referring to the spring ifigeind the spr ngs, of the-modifies forms-oi the "damper, tneter-m .tirubberi will-be .used and it-shoula be snunderstflfldwthat i i-t rm 71$ :maeant either 3 natural rubber or any synthetic rubber or plastic material having the characteristics of resilience and elasticity inherent in resilient natural rubher.

The housing It may comprise part of a fan belt pulley structure for use on the crankshaft of an automotive engine (not shown) for vibration absorbing purposes. For this purpose the housing 10 has at one side an annular radially outwardly opening channel-shaped flange M defining a pulley groove. A central tubular hub 15 is provided for attaching the pulley-damper unit to the crankshaft.

Since the inertia mass [2 in order to be eifective for damping the torsional oscillations or vibrations of the crankshaft with which the unit may be associated must be in the form of a rotary mass or flywheel, the chamber I! provided by the housing for the inertia mass is herein preferably in the form of a generally axially opening annular channel, and the inertia mass [2 is in the form of a ring or wheel which is assembled into the housing through the open side thereof. Thereafter, the housing is closed by an annular closure disk or plate or cover Ill. The margins of the cover are received on respective rabbet groove shoulders i8 and the margins of the housing defining the mouth of the chamber H are turned over onto the margins of the cover plate as shown at I9 to secure the cover plate permanently and in fluid-tight relation to the housing.

A tuned relationship of the inertia mass 2 to the housing 10 requiring a spring of only relatively small proportions, that is, a small size spring, is afforded by the rubber spring [3 which is secured between the inner periphery of the inertia mass ring i2 and the inner periphery of the walls defining the chamber ll within the housing. For various tuning requirements, of course, both the radial and axial dimensions of the rubber spring l3 with relation to the housing and inertia mass can be varied, or either of these dimensions canbe varied in calculated respects. In any event, the rubber spring is in fixed attachment to both the housing and the inertia mass. This can be effected by bonding or other surface adhesion. It will be observed that the axial sides of the spring l3 as well as the axially facing sides and the outer periphery of the inertia mass l2 are in spaced relation to all of the opposing surfaces within the chamber ll. As a result, torsional movements of the housing will, through the rubber spring coupling [3 cause the inertia mass [2 to move with the housing. However, the inertia mass will tend to continue its momentum despite torsional movements of vibrational nature out of phase with the normal momentum of the housing l0, and the resilience of the rubber spring l3 will normally enable the inertia mass to resist disturbance in its momentum by such vibrations.

When the vibrations in the housing [0 as transmitted thereto by the mass to be damped with which the housing is operatively connected, reach a natural frequency for which the damper is tuned through the spring l3, counteracting vibration is induced in the flywheel or inertia mass l2 and the counteracting force thus generated operates through the spring 13 upon the housing ID to dampen or dissipate the natural frequency vibration.

Ordinary torsional vibrations transmitted from the mass to be damped to the housing H! are damped by shear films of viscous fluid between the opposing working surfaces of the inertia mass l2 and the surfaces defining the inside of the chamber H. For this purpose, the axially facing and outer peripheral surfaces in opposing relation of the inertia mass and the chamber are predetermined to accommodate but shear films of a viscous fluid in the spacing or clearance therebetween. A viscous fluid for this purpose may be a selected silicone. Such a viscous fluid has the attributes of proper viscosity rating for the purpose desired, substantially uniform viscosity throughout a wide temperature range, and it is readily available commercially. The viscous fluid is filled into the chamber 1 l through means such as openings 20 in the cover plate H which are suitabiy sealed as by welding 2| after the fill has been accomplished. By resistance to relative parallel movement of the working surfaces of the inertia mass 12 and the chamber H, the viscous fluid coupling dampens the torsional vibrations.

Where the tuning requirements are greater than can be accommodated by an inner peripheral rubber spring i3 as shown in Figs. 1 and 2, for any particular installation, the modifications shown in Figure 3 may be utilized. In this form, a casing or housing 30 provides a chamber 3| for an inertia mass 32 having a rubber spring coupling 33 with the housing. In thi instance, the rubber spring 33 is secured between an axially facing surface of the inertia mass 32 and the opposing axially oppositely facing surface within the chamber 3! with the peripheral edges of the spring 33 and of the inertia mass 32 as well as the opposite axially facing surface of the inertia mass being in spaced relation to the opposing surfaces defining the housing chamber 3!. Through this arrangement, a rubber tuning spring of substantially greater mass is attained. The inner and outer peripheral as well as the free axially facing surfaces of the inertia mass are in shear film spaced relation to the opposing surfaces within the casing and the spaces are filled with viscous fluid so that viscous damping of vibrations at amplitudes other than a natural frequency amplitude vibration is accomplished. The natural frequency vibration is counteracted by action of the inertia mass through the rubber spring coupling 33.

In Figure 4 is shown a vibration damper construction wherein the rubber spring coupling is substantially increased over that of the form of Figure 3. To this end, a casing 40 having an inertia mass chamber 41 houses an inertia mass or flywheel ring 42 which is connected to the housing by means of a rubber spring 43. In this form the rubber spring connects not only the inner peripheral surface of the flywheel or inertia mass 52 but also one of the axially facing surfaces of the inertia mass. This affords a rubber spring of quite large mass. The remaining axially facing surface and outer peripheral surface of the inertia mass &2 cooperate in spaced opposition to the opposing surfaces within the housing 46 to afford shear film spacing therewith filled with a viscous damping fluid so that a com bination of viscous damping and tuned damping is attained.

For some purposes the form of Figure 5 will be more adequate by providing a rubber spring of a mass different from that attained by the forms of damper described hereinabove. To this end, a casing or housing 50 has therein a chamber 5! housing an inertia mass or flywheel ring 52 which is attached to the housing through the medium of a rubber spring 53 connecting the outer periphery of the flywheel ring to the outer periphery defining the chamber 5!. The axially facing edges of the rubber spring 53 are in spaced relation to the opposing surfaces of the housing. Both of the opposite axially facing surfaces of the inertia ring 52 and the inner peripheral edge of the inertia ring are in shear film spaced relation to the opposing surfaces of the housingand the chamber is filled with viscous fluid providing shear films between the opposing working surfaces.

In the form of Figure 6, a, relationship of rubber spring to inertia mass and housing is provided for wherein the rubber spring is of large mass compared to the inertia ring. To this end, a housing 8i! has an inertia mass chamber (if housing an inertia mass 62 which is coupled to the housing by a rubber spring 63 at one axially facing side and at its outer periphery. The inner peripheral and the exposed axially directed edge surfaces of the rubber spring are in spaced relation to the opposing surfaces of the housing, and the inner peripheral surface and the free axially facing surface of the inertia mass are in shear film spaced relation to the opposing surfaces of the housing, with Viscous damping fiuid providing shear film couplings therebetween.

In all forms of the invention, the rubber coupling springs afford an economical, efficient spring coupling which is especially suitable for use where premium on available space is a factor in design for any particular application. The rubber springs afiord high spring efficiency in lowunit mass by reason of the relative density of the rubber and the high degree of resiliency per unit mass of the rubber springs. Internal frictional heat that may develop in the rubber springs is distributed and dissipated by the viscous fluid to parts of the housing remote from the springattached portions of the housing, and thereby overheating or at least undesirable heating of the rubber springs is avoided. In each instance it will be observed that the rubber springs main-- tain the respective associated inertia masses in substantially proper shear film spaced relation to the opposing surfaces within the housing.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. In combination in a vibration damper, a housing structure providing a fluid-tight chamber, an inertia mass structure housed within said chamber and relatively movable therein, a viscous damping fluid within the housing, said housing structure and said inertia mass structure having opposed parallel working surfaces which are in essentially linear velocity gradient spacing relative to the viscosity of the damping fiuid and have a shear film of the fluid therebetween, such shear film being thicker than a mere lubricating film but being of less thickness than a layer of the fiuid which would afford only a non-linear velocity gradient relationship, said shear film of the fluid acting between said working surfaces to resist relative parallel movement thereof, and a rubber tuning spring connecting a surface of the inertia mass structure to the housing within said chamber.

2. A vibration damper according to claim 1 wherein the housin and the inertia mass structure are annular in form and said rubber tuning spring is also annular in form.

3. A vibration damper according to claim 2 wherein the annular rubber tuning spring is iriterposed between the inner peripheral surface of the inertia mass structure and the opposing surface of the chamber.

4. A vibration damper according to claim 2 wherein the rubber tuning spring is interposed between an axially facing surface of inertia mass and the opposing axially facing surface of the chamber.

5. A vibration damper according to claim 2 wherein the annular rubber tuning spring is interposed between the outer peripheral surface of the annular inertia mass structure and the opposing surface of the chamber.

6. A vibration damper accordin to claim 2 wherein the rubber tuning spring is interposed between the inner peripheral surface and also an axially facing surface of the inertia mass and the opposing surfaces of the chamber.

7. A vibration damper according to claim 2 wherein the rubber tuning spring is interposed between the outer peripheral surface of the annular inertia mass and an axially facing surface of the inertia mass and the opposing surfaces of the chamber.

8. In combination in a vibration damper, a housing having a closed chamber, said chamber having a plurality of angularly related surfaces, an inertia mass housed within said chamber and having surfaces opposing the chamber surfaces, a rubber tuning sprin in secure engagement with one of the surfaces of the inertia, mass and the opposing surface of the chamber and supporting said inertia mass in fully spaced relation within the chamber, said tuning spring being spaced from all surfaces within the chamber except the surface against which it is secured, and a viscous damping fluid within said chamber interposed between the surfaces of the inertia mass and the chamber except where the tuning spring engages between opposing surfaces of the inertia mass and the chamber.

.9. In combination in a rotary vibration damper for damping torsional vibrations in a crankshaft or the like, a housing having a hub adapted to be attached to the crankshaft for rotation of the housing with the crankshaft, said housing having an annular chamber having an annular opening thereinto, a closure plate sealingly closing said opening and providing with the other surfaces in the chamber a plurality of angularly related opposite radially facing and oppositely axially facing surfaces, an annular inertia mass in said chamber and spaced from all of the surfaces in the chamber, an annular rubber tuning spring secured between certain opposing surfaces of the inertia mass and the housing and supporting the inertia mass in said spaced relation, and a viscous damping fluid interposed between all of the free spaced opposing surfaces of the inertia mass and the housin within the chamber.

BERNARD E. OCONNOR.

References Cited in the file of this patent UNITED STATES PATENTS Number 

